Renewable electric fuse



F. C. LA MAR AND P. 1. HOPKINS.

BENEWABLE ELECTRIC FUSE.

APPLICATION FILED Aue. 16. 191s. RENEwEn MAn.1o.1921.

1,376,342. Patented Apr. 26, 1921.

section thereof.

` ably brass,

UNITED STATES PATENT OFFICE.

rmx c. LA man AND rama .'r. HOPKINS, or PITTSBURGH, rmmsnvmm .BENEWABLE ELECTRIC FUSE.

Application led August 16, 1918,

To all whom it may concern.' Y

Be it known that we, FRANK C. LA MA1: and PETER J. HOPKINS, citizens of the United States, residing at Pittsbur h, in the county of Allegheny and State of ennsylvania, have invented a certain new and useful Improvement. in Renewable Electric Fuses, of which the following is a specification.

This invention relates to electric .fuses of the renewable type, and the object of the invention is to provide a renewable or refillable fuse of simple, economical and eiicient construction, and which 1s easlly and readily assembled, and as easily and readlly disassembled when blown or the fuse element becomes disrupted by an excess or overload current, for the purpose of1 recharging or refilling the fuse with a new fuse element. The invention consists in the details of construction and combination of parts, all substantially as we will ynow proceed more particularly to set forth and iinally claim.

In the accompanying drawings, illustrating the invention,-1n the several figures of which like parts are similarly deslgnated, Figure 1 is a side elevation of the assembled fuse. Fig. 2 is a horizontal longitudinal Fig. 3 is a vertical longilooking in the direction of 2, the fuse element and being shown in elevation. Fig. 4 is a partly sectional and elevational view of the casing and its attached ferrule. Fi 5 is an end view of the assembled fuse of ig. 1, and Fi 6 is an end viewof the casing shown in 4, looking in the direction of the arrow As shown in the drawings, the fuse comprises a tubular shell or casin 1 of ber, or any suitable substantially re ractory and insulating material, having 'one of its ends slightly reduced, diametrically opposite notches 6, and fitted upon this reduced end is a metal, preferferrule 4, provided with diametrically opposite ears 5, and as herein shown these ears 5 are preferably formed by cutting slits in the edges of: the errule and bending the slitted portions inwardly, said ears enterin the notches 3 in the end of the casing. crews 6 are screwed into or otherwise fixed in the ears 5 and project beyond the end of the casing to receive knurled nuts 7 for a purpose presently aptudinal section, the arrows Fig. terminal blades Specication of Letters Patent.

at 2, and provided with Patented npr. 26, 1921.

SeriaLNo. 250,173. 'Renewed March 10, 1921. SerialiNo. 451,330.

thereupon and having in its end wall a central elongated opening 9 for the passage of the knife-blade or terminal to which the fuse element is connected, and openin s 10 upon opposite sides of the o ening '9 or a Ipurpose presently to be descrlbed. The end cap 8 may be permanently fixed to the end of the casing 1n any suitable manner, but as hereln shown it is removably attached to the casing.

The fuse element 11 may be of any suitable or well .knownlconstructiom but prefer-- ably one which is provided with one or more b low-out or readily fusible restricted portions 12 between its ends, the ends ofsaid fuse element being electrically connected, as by bolts. or screws 13 and nuts 14, or any other .suitable readily detachable fastenings, to knlfe-blades or terminals 15 and 16.

.The knife-blade or terminal 15, is provlded with a cross-bar 17 constructed of a thm, flat, straight piece of metal of less width than the blade, passed through and.v snugly fitting an opening 18 therein, adjacent to its connection with the fuse element and brazed or otherwise rigidly and permanently iiXed therein. Screws 19 are fixed in the .opposite ends of the cross-bar 17 and project outwardly beyond the end of the caslng, and are adapted to receive knurled nuts 20 when the fuse is assembled, as hereinafter described.

The knife-blade or terminal 16 .is also procentral elongated opening 25 for the pas-k sage of the knife-blade or terminal 16, and openings 26 upon opposite sides of the opening 25, for the passage of the. screws 6, which project beyond the end of` the cap and are adapted to receive the knurled nuts 7, to lock the parts in place.

The end caps 8 and 24 may be addition ally secured 1n place by set-screws 27 carred by the casing or shell and engaging .slots in the edges of the end caps.

. erly positioned 'so that its cross-bar 17 will pass between the inwardly projecting ears 5 of the ferrule, and the fuse element and bladesare then moved inward and turned l projected beyond the said cross-bar.

until the blade 15 alines with and passes through the elongated slot or opening 9 in the end cap 8, and the screws 19 carried by the cross-bar 17 thereby brought into alinement with the openings 10 in the end cap 8, when by further inward movement of the `fuse element and knife-blades, the knifebiade 15 and the screws 19 will be projected through their respective openings, and at the same time" the openings 23 in the crossbar 21 carried by the knife-blade 16, will registerwith and pass over the screws 6 fixed to the ears 5 of the ferrule 4 andmle e end cap 24C may then be laced upon the knife-blade 16, by passing tiie biade through the opening in the end cap, and forced upon the end of the casing, the holes 26 registering with and passing over the screws 6 which project beyond the end cap, and the nuts 7 then itted upon the screws 6 and 'turned up to secure theA parts in place. The nuts 2O are then placed upon the projecting ends of the screws 19 atv the opposite end of the fuse and turned up tight to firmly hold the arts in place at this end of the `fuse. hen the fuse is blown or disrupted by an excess or overload current, and it is desired to remove the damaged fuse element and replace it by a new one, it is only necessary to remove the nuts 7 and 20 at the opposite ends of the fuse, and remove the,l end cap 24, when the knife-blades and the parts of the damaged fuse element may readily be removed from the casing, and a new fuse element afixed to the knife-blades or terminals, and the fuse reassembled as hereinbefo-re described. Or, both the end caps 8 and 24: may be detached'frorn the ends of the casing for removing the damaged parts of the fuse element.

Although the invention is herein illustrated as applied to a knife-blade type of fuse, we wish to be understood as not limiting the invention to this specific' application thereof, as the construction is equally ap- 'plicable to the ferrule type of fuse, as it will be seen that it would only be necessary to omit the projecting blade portions of the terminals or fuse element carrying parts to provide a fuse of the ferrule type.

It is also to be understood, that we do not limit the invention to.y the exact detailsl of construction herein shown and described, as the same may be changed in various particularsand still be within the scope of the appended claims.

What we claim is:

1. A renewable electric fuse, comprising a tubular casing of insulating material, having notches in one of its ends, a ferrule fitted upon the notched end thereof and provided with inwardlyI projecting ears passing through said notches, screws fixed in said ears and rojecting beyond the end of the casing, a use element and terminals to which it is connected for supporting the fuse element in the casing, said terminals having cross-bars fixed therein, one of said cross-bars provided at its ends with openings adapted to engage the screws projecting from said ears, an end cap lfitted upon the end of the casing over said ferruie and.

provided with openings for the passage of' said screws, nuts screwed upon the projecting ends offsaid screws for locking the parts in place, and means for securing the cross-bar of the other terminal in the end of the casing at the opposite end of the fuse. 2. -A renewable electric fuse, comprising a tubular casing of insulating material having a reduced end and diametrically ar.- ranged notches therein, a ferrule fixed on said reduced end and provided with ears' projecting inwardly through the said notches, screws fixedv in the ends of said ears and projecting beyond the end of the r casing, terminal blades for supporting a fuse element in said casing, one of said blades having a cross-bar projecting from opposite sides thereof and having screws fixed therein and adapted to project beyond the end of the-casing, and the other of said blades having a cross-bar projecting from opposite sidesthereof and provided with openings adapted to engage the screws fixed in the ears on said ferrule, end caps -ftted uponthe ends of the casing and provided wlth openings through which the terminal blades and the ends of said screws pass, andnuts adapted to be fitted upon said screws for locking the arts in place.

In testimony whereo we have hereunto 

